<?php

namespace ZX\Tool;

use PDO;
use PDOException;

class Mysql
{
    private $type;      //数据库类别
    private $host;      //主机地址
    private $port;      //端口号
    private $dbname;    //数据库名
    private $charset;   //字符集
    private $user;      //用户名
    private $pwd;       //密码
    private $pdo;       //保存PDO对象
    private static $instance;

    private function __construct($param)
    {
        $this->initParam($param);
        $this->initPDO();
        $this->initException();
    }

    private function __clone()
    {
    }

    public static function getInstance($param = array())
    {
        if (!self::$instance instanceof self)
            self::$instance = new self($param);
        return self::$instance;
    }

    //初始化参数
    private function initParam($param)
    {
        $this->type = $param['type'] ?? 'mysql';
        $this->host = $param['host'] ?? '127.0.0.1';
        $this->port = $param['port'] ?? '3306';
        $this->dbname = $param['dbname'] ?? 'sel';
        $this->charset = $param['charset'] ?? 'utf8';
        $this->user = $param['user'] ?? 'root';
        $this->pwd = $param['pwd'] ?? '';
    }

    //初始化PDO
    private function initPDO()
    {
        try {
            $dsn = "{$this->type}:host={$this->host};port={$this->port};dbname={$this->dbname};charset={$this->charset}";
            $this->pdo = new PDO($dsn, $this->user, $this->pwd);
        } catch (PDOException $ex) {
            $this->showException($ex);
            exit;
        }
    }

    //显示异常
    private function showException($ex, $sql = '')
    {
        if ($sql != '') {
            echo 'SQL语句执行失败<br>';
            echo '错误的SQL语句是：' . $sql, '<br>';
        }
        echo '错误编号：' . $ex->getCode(), '<br>';
        echo '错误行号：' . $ex->getLine(), '<br>';
        echo '错误文件：' . $ex->getFile(), '<br>';
        echo '错误信息：' . $ex->getMessage(), '<br>';
    }

    //设置异常模式
    private function initException()
    {
        $this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    }

    //执行增、删、改操作
    public function exec($sql)
    {
        try {
            return $this->pdo->exec($sql);
        } catch (PDOException $ex) {
            $this->showException($ex, $sql);
            exit;
        }
    }

    //获取自动增长的编号
    public function lastInsertId()
    {
        return $this->pdo->lastInsertId();
    }

    //判断匹配的类型
    private function fetchType($type)
    {
        switch ($type) {
            case 'num':
                return PDO::FETCH_NUM;
            case 'both':
                return PDO::FETCH_BOTH;
            case 'obj':
                return PDO::FETCH_OBJ;
            default:
                return PDO::FETCH_ASSOC;
        }
    }

    //获取所有数据 ，返回二维数组
    public function fetchAll($sql, $type = 'assoc')
    {
        try {
            $stmt = $this->pdo->query($sql);  //获取PDOStatement对象
            $type = $this->fetchType($type); //获取匹配方法
            return $stmt->fetchAll($type);
        } catch (Exception $ex) {
            $this->showException($ex, $sql);
        }
    }

    //获取一维数组
    public function fetchRow($sql, $type = 'assoc')
    {
        try {
            $stmt = $this->pdo->query($sql);  //获取PDOStatement对象
            $type = $this->fetchType($type); //获取匹配方法
            return $stmt->fetch($type);
        } catch (Exception $ex) {
            $this->showException($ex, $sql);
            exit;
        }
    }

    //返回一行一列
    public function fetchColumn($sql)
    {
        try {
            $stmt = $this->pdo->query($sql);
            return $stmt->fetchColumn();
        } catch (Exception $ex) {
            $this->showException($ex, $sql);
            exit;
        }
    }
}

